PIR sensor + Relay Module + Blynk

I am making a home automation that turns on and off when it detects motions or when turned on by using blynk by the user. but everytime i turn on the relay it turns off after seconds, how to fix?

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
int pirPin = 14;
int relayPin = 5;
int pirValue;

char auth[] = "xxxxxxxxx";

char ssid[] = "xxxxxxxxxxxx";
char pass[] = "xxxxxxxxxxx";

void setup()
{
  Serial.begin(115200);
  Blynk.begin(auth, ssid, pass);
  pinMode(pirPin, INPUT);
  pinMode(relayPin, OUTPUT);
}

void pirSensor()
{
  pirValue = digitalRead(pirPin);
  Blynk.virtualWrite(V0, pirValue);
}

void loop()
{
  Blynk.run();
  pirSensor();
  if (pirValue == HIGH)
  {
    digitalWrite(relayPin, LOW);
  }
  
  else
  digitalWrite(relayPin, HIGH); 
}